Design Changes In Galleries Header

[ioannakok]

Design has given us some changes for the galleries header for after switching galleries rendering to DCAR:

https://www.figma.com/design/yXvqv6fZP5uxfBhAmEFBV3/Webex-Tools-Product-Discovery?node-id=187-234&t=ZNhQbQyceYYvYDva-0

[ioannakok]

Some work has been done here:

• Design tweaks in galleries meta #14571
• New caption / standfirst / meta Gallery design #14573